Continuous quenching apparatus

ABSTRACT

A quenching apparatus that comprises a support circumferentially and spacedly disposed relative to an object to be quenched, with a relatively closely spaced array of jet structures to which cooling fluid is supplied being slidably mounted on the support. Anti-friction means on each of the jet structures are biased into contact with the object for adjustably moving the corresponding jet structures on the support to maintain a selected clearance relative to the object. The jet structures may be selectively adjusted relative to each other to accommodate different sized objects to be quenched. The individual jet structures consisting of a jet opening and a fluid directing spoon are disposed at a relatively small angle to the adjacent surface of the object. An axial series of supports, each provided with an array of jet structures, has the angle of direction of the jet increasingly inclined to the surface of the object going from the entrance support to the exit support.

United States Patent Hollyer et a1.

[ 1 Mar. 21, 1972 [54] CONTINUOUS QUENCHING APPARATUS [72] Inventors: John R. Hollyer, Warrington, Pa.; Robert A. Andreas, Homewood, Ill.

[73] Assignee: Drever Company, Huntington Valley, Pa.

[22] Filed: Nov. 12, 1969 [21] Appl. No.: 875,769

[56] References Cited UNITED STATES PATENTS 2,578,804 12/1951 Holveck et a1 134/l99 X 2,726,897 12/1955 Dupont ..239/523 X 3,399,685 9/1968 Jones et a1. ..134/64 1,672,061 6/1928 George ..l34/122 1,575,526 3/1926 Bocher ..l34/199 UX 3,015,862 l/l962 Rustemeyer et a1. ..164l283 X Primary Examiner-Robert L. Bleutge AttorneyBuell, Blenko & Ziesenheim 57 ABSTRACT A quenching apparatus that comprises a support circumferentially and spacedly disposed relative to an object to be quenched, with a relatively closely spaced array of jet structures to which cooling fluid is supplied being slidably mounted on the support. Anti-friction means on each of the jet structures are biased into contact with the object for adjustably moving the corresponding jet structures on the support to maintain a selected clearance relative to the object. The jet structures may be selectively adjusted relative to each other to accommodate different sized objects to be quenched. The individual jet structures consisting of a jet opening and a fluid directing spoon are disposed at a relatively small angle to the adjacent surface of the object. An axial series of supports, each provided with an array of jet structures, has the angle of direction of the jet increasingly inclined to the surface of the object going from the entrance support to the exit support.

10 Claims, 4 Drawing Figures CONTINUOUS QUENCI-IING APPARATUS The present invention relates to quenching apparatus and more particularly to continuous quenching apparatus which can be associated with a production line for various elongated shapes such as tubular products, large diameter line pipe, bars, rods, extrusions, sections, and billets.

The science of heat transfer has been known in detail for centuries but has never been properly applied to the mechanics of quenching. In general the haphazard approach of prior practices has resulted in poor dimensional stability and uneven transformation which cause distortion and quench cracking owing to the nonuniform cooling. In the case of pipe and bar or other elongated shapes, it has been frequently necessary to straighten the shapes following quenching in order to remove camber or the like introduced by the nonuniform application of the quenching fluid. Such straightening introduces undesirable cold working stresses.

Although many attempts have been made to adapt various types of quenching apparatus to continuous or automated production lines, for example the U.S. Pats. to Scott No. 2,776,230 and to Waddington et al. No. 2,623,531, none of these attempts has been eminently successful. For the most part, previous continuous quenching apparatus has relied upon various types of cooling sprays to apply an atomized quenching fluid such as water. This arrangement fails to transfer a sufficient volume of quenching fluid within a given period and at a proper velocity to obtain an optimum heat transfer coefficient. In consequence, the entire production line must be slowed to a speed determined by the quenching apparatus which then becomes a production bottle neck. In addition to a serious loss of production, the rapidity of cooling is not sufficient to achieve maximum characteristics in the finished product. As is well known there are a wide variety of quenching procedures, any of which require instantaneous cooling or quenching, as an ideal or limiting case, to bring out the maximum hardness, or other characteristic of which the product is inherently capable. In this latter connection, none ofthe known continuous quenching mechanisms is capable of confining the quenching fluid to a small area of applications so as to provide the maximum heat transfer coefficient or a cooling curve of maximum slope. A back flow of the quenching fluid, for example, increases the cooling or quenching time and results in a product with inferior characteristics. The importance of confining the quench to the narrowest possible time interval is discussed below.

The inability of prior continuous quenches to afford an adequate heat transfer coefficient is illustrated remarkably by the U.S. Pat. to Huseby No. 3,294,599 wherein a complicated mandrel is inserted through the interior of a tubular member to apply quenching fluid to both the external and internal surfaces of the tubular member. The Huseby arrangement obviously would be inappropriate for quenching solid elongated shapes and cumbersome in operation for tubes or casings of considerable length. Our mechanism evinces a heat transfer coefficient of sufficient magnitude with reference to the outer surface, only, of the product.

It is well known, at least in academic circles, that nonuniform cooling causes uneven phase changes resulting in bowing, cambering, cracking and other dimensional distortions which are unacceptable in the finished product. A properly and uniformly applied quench will not introduce dimensional distortions which were not already present prior to the quenching procedure. Although the importance of a completely uniform application of the quenching fluid is selfevident there is no known continuous quenching apparatus for accomplishing this. A proper quench is provided by our present invention which eliminates the necessity of straightening the elongated shapes following the quenching operation and assuming that the product is in a straightened condition prior to quenching.

A number of prior attempts (typified for example by the U.S. Pats. to Scott No. 2,776,230; Huseby No. 3,294,599 and Waddington et al. No. 2,623,531) have been made to provide uniform distribution of quenching fluid about the adjacent periphery of the elongated shape, which is intended to be centered within the quenching apparatus. In these prior arrange ments there is no assurance that the elongated shape will remain centered within the circularized jet structure. As the heat transfer coefficient varies inversely with the square of the distance from the individual spray devices it is evident that any small lateral deviations of the product path or of the product dimensions as the latter moves past the spray mechanism will assume considerable importance. The same applies to unintentional dimensional distortions which may have been unavoidably introduced into the product prior to the quenching operation. The aforementioned and other prior structures have no means for precisely establishing a specified distance between the source of the quenching fluid and the adjacent periphery of a relatively moving product, particularly where there may be lateral deviations for any of the aforementioned reasons. Further, there has been no previous disclosure, insofar as we are aware, of means for laterally or radially moving or adjusting individual components or jets of the quenching fluid supply relative to lateral deviations of an adjacent portion of the moving product surface. By the same token, prior apparatus is capable of accommodating shapes of only a given cross sectional configuration.

We have found, in contrast to previous approaches to this problem and in contrast to the teachings of the prior art (for example Scott U.S. Pat. No. 2,776,230) that a water curtain or solid sheet of water is the most effective quenching medium, provided that it can be uniformly applied. In further contrast to the teachings of the prior art, we have established that the use of atomizations or other relatively finely divided sprays of quenching medium cannot effectively penetrate the blanketing film which forms about the elongated shape. This film, sometimes referred to as a steam film, is formed by nucleate boiling of the quenching medium as it contacts the extremely hot surface of the product being quenched. The steam film provides an excellent, but highly undesirable, insulation between the quenching medium and the surface of the product. The heat transfer coefficient, therefore, is reduced drastically and with it the slope of the cooling curve. Prior quenching apparatus is incapable therefore of a substantially complete conversion, for example, of austenite to martensite, which must be accomplished within a narrowly specified time interval. We have overcome this particular aspect of the quenching problem by directing a water curtain, as it were, onto the moving product with sufficient velocity, pressure and volume to penetrate the steam film and to increase drastically the heat transfer coefficient which would otherwise attain. The span of the quenching interval is attendantly reduced. As noted above, this water curtain is precisely and uniformly maintained so that the steam is uniformly penetrated and the heat transfer coefficient is otherwise maintained constant about the periphery of the moving product. In penetrating the steam film and in avoidance of the problems connected with back flowing we have also found that a particular range of angulation of the water curtain is desirable.

In this respect, although the prior art recognizes that some angulation is desirable, a proper angulation or range of angulation has not been disclosed. For example, in Huseby U.S. Pat. No. 3,294,599 where a number of sprays are applied in seriatim along the length of a moving pipe, there is no concept of successive variation in the spray angles.

Our novel quenching apparatus is suitable for a wide variety of quenching and cooling applications. For example, in quenching line pipe, bars, casings, and other elongated shapes, maximized properties are obtainable when austenitized steel at about l,600 F. is transformed to the maximum percentage of which low alloy steel is inherently capable at the critical transformation point. It is well known that the attendant temperature drop must be accomplished within a well defined time schedule for maximum conversion of austenite to martensite. With the heat transfer coefficient provided by our quenching apparatus a conversion in excess of percent can be accomplished in most applications, depending upon thermal diffusivity and ultimate hardenability. It is essential to complete the conversion of austenite to martensite in a very short time. In any event, some 30 percent better results are attained by our invention than with any prior quench of which we are aware.

Many grades of steel, for example high-alloy aircraft steels, are conventionally airor oil-quenched because of the inability of conventional water quenching systems to apply a uniform quench. Many manufacturers have a baseless fear of thermal shock even from a properly applied water-quench. Thermal shock, however, is caused not by the more rapid temperature drops of a water-quench but rather by nonuniform application of the cooling water. It is anticipated that with our invention and its uniform application of quenching water, high-alloy steels will increase the values of their metallurgical characteristics by as much as 50 percent in contrast to an oil-or airquench. For similar reasons, many manufacturers have resorted to oilor air-quenches for elongated shapes to prevent bowing or other dimensional distortion. In an oilor air-quench the effects of nonuniform application of the cooling medium are much less evident as the quenching occurs over a correspondingly longer period of time. However, the improvement in dimensional stability is attendant upon sacrifree of maximum metallurgical characteristics, owing to the gentler slopes of the cooling curves. With a uniform water quench, as provided by our invention, an improved quench is afforded along with superior dimensional control.

Our quenching apparatus also is desirable for various types of austenitic steels wherein other metallurgical changes are effected instead of the conversion from austenite to martensite. In a typical application, austenitic steel at about l,900 F. is cooled to a temperature of about l,0O F. The quench desirably is made as quickly as possible to produce maximum physical properties and freedom from carbide precipitation at the grain boundaries. Here again a uniform quench is necessary to maintain dimensional stability in the product.

Our apparatus also is useful in temper-quenching in which the product may be air-tempered at l,l00-l,500 F. and subsequently cooled to about 750 F. This type of quenching must also be made as rapidly as possible to avoid temper embrittlement from a secondary precipitation of carbide.

We accomplish these desirable results and overcome the aforementioned difficulties of the prior art by providing quenching apparatus comprising a support circumferentially and spacedly disposed relative to an object to be quenched, a relatively closely spaced array of jet structures slidably mounted on said support, means for moving each of said jet structures to a selected position on said support relative to said object, and means for supplying a cooling fluid to each of said jet structures.

We also desirably provide similar quenching apparatus wherein each of said jet structures includes anti-frictional means for contacting said object, said anti-frictional means being disposed on said jet structure so as to space said jet structures predetermined distance from the respectively adjacent surface of said object.

We also desirably provide similar quenching apparatus wherein biasing means are coupled to each of said jet structures for urging said jet structures towards said object.

We also desirably provide similar quenching apparatus wherein said moving means are capable of withdrawing selected ones of said jet structures to accommodate an object having a different or smaller cross sectional configuration.

We also desirably provide similar quenching apparatus wherein said supplying means include a ring header mounted adjacent said support and circumferentially surrounding said object, and a plurality of flexible conduits are coupled to said header and to said jet structures.

We also desirably provide similar quenching apparatus wherein a plurality of said supports are so provided, each of said supports having a similar array of said jet structures, said array extending axially of said object.

' preferred methods of practicing the same.

In the accompanying drawings we have shown certain presently preferred embodiments of the invention and have illustrated certain presently preferred methods of practicing the same, wherein:

FIG. 1 is a perspective view of one form of continuous quenching apparatus arranged in accordance with our invention;

FIG. 2 is a front perspective view of the apparatus as shown in FIG. 1;

FIG. 3 is a partial front elevational view of an alternative disposition of the apparatus of FIG. 2 for handling small diameter shapes;

FIG. 3A is a cross sectional view of the apparatus shown in FIG. 3 and taken along reference line IIIAIIIA thereof.

With more particular reference to the drawings, the continuous quenching apparatus 20 includes in this example an upper support 22 and a lower support 24. Spaced along the length of the lower support are a number of cross braces 26 with which are aligned a like number of supporting brackets 28 forming part of the upper support 22. A supporting disc 30 of annular configuration is secured to each of the cross braces 26 and in turn to the associated one of the upper brackets 28. Each of the supporting discs 30 supports a number of radially disposed and slidably mounted jet structures or carriages 32 which are described more fully below. In this arrangement of our invention a total of eight supporting discs 30 and associated jet carriages 32 are utilized, although a greater or lesser number can be employed depending upon the application of the invention. The supporting discs 30 are spaced axially along and circumferentially surround an elongated pipe, bar or other shape 74 (FIGS. 3 and 3A) to be quenched.

As best shown in FIGS. 1 and 3A a peripheral ring header 34 spacedly surrounds the outer edge of each of the discs 30. Each of the ring headers 34 is likewise joined to the associated bracket 28 and cross brace 26 by a number of U-bolt clamps 36. Each ring header 34 includes an inlet port 38 and a number of outlet fittings 40 to which are respectively joined a like number of flexible conduits 42. The other end of each of the conduits 42 is connected to the fluid inlet 44 of the associated jet structure 32. The use of the flexible conduits 42 facilitates the several movements of the jet carriages 32 for the purposes described below.

An axially extending supply header (not shown) can be coupled to each of the ring header inlet ports 38 by a number of connecting conduits of suitable length. The supply header, which can extend longitudinally of the quenching apparatus 20in turn can be supplied through one or more inlet conduits, which can be connected to a suitable source of quenching fluid (not shown) such as water.

As evident from FIGS. 1-3A each of the jet carriages 32 includes in this example a pair of slidably mounted components 52 and 54. The component 52 comprises a jet block 56 on which is mounted a high-velocity, high-volume water jet 58 and a carriage wheel 60 or other anti-frictional means. The wheel 60 which is rotatably mounted by means of pin 62 extends into cavity 64 in the jet block 56 for this purpose. The jet 58 which includes a threaded fitting 66 and a spoon 68 secured thereto for directing the quenching fluid, is likewise mounted on the block 56. The block 56 includes an internal passage 70 which connects the jet 58 to the block inlet fitting 44 and thence through the flexible conduit 42 to the ring header 34.

The jet block 56 is mounted upon a pair of slide rods 72 which together with the jet block 56 comprise the slidable carriage component 52. The slide rods 72 in turn are slidably mounted on the second carriage component 54 but are biased toward a pipe 74 or other elongated shape passing through the quenching apparatus 20. In this example the biasing force is supplied by a pair of coil springs 76 which are mounted within the slide component 54 as best shown in FIG. 3A. The biasing means 76 enable the jet structures 32 to maintain a constant spacing between their jets 58 and the adjacent surface portions of the elongated member 74, as the latter is moved relatively to the quenching apparatus 20.

Each slide component 54 is slidably mounted on an associated slideway defined on the supporting disc 30 by a pair of slide plates 78 secured to the supporting disc, as by welding. The slide component 54 is adjustably secured in a selected position along the length of the slideway defined by the plates 78 by means of a drawbolt 80 and guide bolt 82. The drawbolt 80 threadedly engages a supporting bracket 84 secured in this example to the slide plates 78, while movement of the guide bolt 82, when loosened, is delimited by slot 86 formed in the supporting disc 30 and disposed between the slide plates 78. The drawbolt 80 is rotatably connected at 88 to the upper end of the slide component 54, as best shown in FIG. 3A.

Upon loosening nuts 90, 92 the drawbolt 80 is rotated to position the slide component 54 of the jet carriage 52 such that wheel 60 of the jet block 56 engages the adjacent surface of the elongated shape 74 passing through the quenching apparatus. The slide component 54 can be adjusted farther toward the elongated shape 74 so that coil springs 76 preload the wheel 60 against the surface of the elongated shape 74 to a predetermined degree. The engagement of the wheel 60 with the shape 74 precisely determines the proper position of the associated jet 58 relative to the surface of the shape 74 and this precise position is maintained throughout the quenching operation by the biasing means 76.

Desirably the spoon 68 of the jet 58 is shaped such that the quenching fluid is delivered at a particular angle relative to the adjacent surface of the elongated article 74 passing through the quenching apparatus. The inside surface 94 of the spoon 68 is relatively shallow (FIG. 3A) so that the high velocity water or other coolant from jet opening 96 is fanned out to a predetermined extent and thus joins similar coolant jets from adjacent spoons 68 to form a continuous and uniform water curtain extending about the adjacent periphery of the elongated product 74. With the product 74 travelling in the direction denoted by arrow 98 there is virtually no back flow of the coolant as the coolant can be delivered at a very high velocity and at a relatively shallow angle, as shown in FIG. 3A.

As best shown in FIG. 2 a number of the jet carriages 32 are closely spaced about the inner opening 100 of each of the supporting discs 30. For larger diameter pipes all of the jet carriages are adjusted so that their wheels 60 or other contact means engage the adjacent surfaces of the elongated shape. By preloading the jet carriages against the surface of the elongated shape, uniform distances between the jet spoons 68 and the adjacent surfaces is assured irrespective of lateral deviations in travel, or in physical dimensions of the shape. For shapes having smaller cross sectional configurations as better shown in FIG. 3 some of the jet carriages 32 can be withdrawn, in this example to their radially outward limits of adjustment, by means of their drawbolts 80. This position is denoted by jet carriage 32d of FIG. 3. The remaining carriages 32e then have sufficient clearance to be moved to points adjacent their inward radial limits of adjustment, if desired, depending upon a specific diameter (or other lateral dimension) of the relatively smaller shape. This arrangement affords a greater degree of adjustment than would otherwise attain, and also permits a larger number of jet carriages 32 to be used with larger cross sectional configurations. Thus a continuous and uniform water curtain can be formed about the elongated shape 74 irrespective of its diameter within the structural limits of the quenching apparatus.

Although withdrawal of the carriages in an alternating array is denoted in FIG. 3, it will be understood that some other appropriate order of withdrawal can be used such as two out of every three jet structures, every third jet structure, etc., depending upon a specific application of the invention or specific size or cross sectional configuration of the product.

In like manner, the jet carriages 32 of each of the supporting discs 30 are arranged in a circumferential array about its central opening 100. Each array of jet carriages 32 can be similarly adjusted. Ordinarily it is contemplated that the distances X between the individual jet spoons 68 and the adjacent surfaces of the pipe or other shape 74 will remain substantially constant for the several arrays of jet carriages 32, although it is contemplated that this distance can be varied from one array of jet carriage to the next. For a given array of jet carriages i.e., the carriages 32 on any one of the supporting discs 30) in the usual quenching operation, it is intended that the distances X shall remain constant to ensure a uniform water curtain about the pipe or other shape 74. However, the distances X can be varied within a given array of the jet carriages 32 depending upon the quenching requirements of a specific application of the invention. The aforementioned distance variations can be effected by changing the diameter of the associated carriage wheels 60 or by making other obvious structural changes.

Depending upon the application of the invention, the annular disposition of the jet spoons 68 can be varied as required. In the quenching apparatus 20, as shown in FIG. 3A, for example, it will be assumed that the elongated member 74 is travelling in the direction denoted by arrow 98. As noted previously, it is extremely important in many quenching operations, that no back flow of coolant take place in order to avoid premature cooling of the product and attendant lesser cooling curve slope. In a specific arrangement, therefore, the jet structures mounted on the two entry discs 30a (FIG. 1) have their jet spoons 68, disposed at a relatively shallow angle relative to the surface of the product 74 as shown for example in FIG. 3A, to virtually eliminate the possibility of coolant back flow. The volume and high velocity of the flow from the jet spoons 68 further militate against coolant back flow.

On the other hand spoons 68 of the jet structures 32 on the intermediate supports 30b can be disposed at an intermediate angle of inclination, which is somewhat more efficient in eliminating steam film." Finally, spoons 68c (FIG. 1) of the jet structures 32 mounted on exit supporting discs 30c desirably are disposed substantially normal to the surface of the product 74. This angulation is most efficient in cutting through the steam film and otherwise tends to provide an increased temperature coefficient in an area where temperature differentials are considerably lower as compared to the entry end of the quenching apparatus 20. The substantially normal disposition of the jet spoons 68c also minimizes entry of cooling water or other quenching fluid into the back end of pipes or casings, when conveyed through the quenching apparatus. It is contemplated of course that other angle dispositions of the spoons 68 can be utilized depending upon a specific application of the invention.

As evident from FIG. 2 the jet structures or carriages 32 on any one of the supporting discs 30 can be angularly or circumferentially displaced relative to the jet structures on an adjacent disc to compensate for any peripheral variation in the water curtain issuing from the jet structures of a given one of the supporting discs. In the arrangement shown in FIG. 2 every other array of jet carriages 32 are so displaced.

From the foregoing it will be apparent that novel and efficient forms of continuous quenching apparatus have been disclosed herein. While we have shown and described certain presently preferred embodiments of the invention and have illustrated presently preferred methods of practicing the same, it is to be distinctly understood that the invention is not limited thereto, but may be otherwise variously embodied and practiced within the spirit and scope of the invention.

We claim:

l. Quenching apparatus comprising a support circumferentially and spacedly disposed relative to an object to be quenched, a relatively closely spaced array of jet structures slidably mounted on said support, means for moving each of said jet structures to a selected position on said support relative to the object, and means for supplying a cooling fluid to each of said jet structures, each of said jet structures including anti-frictional means for contacting the object, said anti-frictional means being disposed on said jet structures so as to space said jet structures predetermined distances from the respectively adjacent surfaces of the object 2. Quenching apparatus comprising a support circumferentially and spacedly disposed relative to an object to be quenched, a relatively closely spaced array of jet structures slidably mounted on said support, means for moving each of said jet structures to a selected position on said support relative to the object, and means for supplying a cooling fluid to each of said jet structures, each of said jet structures including a first slide component slidably mounted on a second slide component, means for slidably and adjustably mounting said second slide component on said support, and biasing means on one of said components for urging the said first slide component of said jet structure into contact with the object.

3. The combination according to claim 1 wherein biasing means are coupled to each of said jet structures for urging said jet structures individually towards the object.

4. The combination according to claim 1 wherein said moving means are selectively operative to so adjust the relative positions of said jet structures on said support as to accommodate objects having different cross sectional configuratrons.

5. The combination according to claim 1 wherein each of said jet structures includes a jet opening and a fluid directing spoon member disposed adjacent said jet opening, said spoon members being shaped so as to form a cooperatively continuous fluid curtain circumferentially surrounding the object.

6. The combination according to claim 5 wherein at least a portion of each of said spoon members is disposed at a relatively small angle to the adjacent surface of the object to prevent back flow of cooling fluid therealong in a direction opposite to the direction of movement of the object.

7. The combination according to claim 1 wherein said supplying means include a ring header mounted adjacent said support and circumferentially surrounding the object, and a plurality of flexible conduits coupled individually to said header and to a corresponding one of said jet structures.

8. The combination according to claim 1 wherein a plurality of said supports are disposed in axially spaced relation, each of said supports having thereon a similar array of said jet structures, said arrays providing a quenching tunnel through which the object to be quenched moves for successive quenching sprays thereby.

9. The combination according to claim 8 wherein the jet structures on one of said supports are circumferentially displaced relative to the jet structures on an adjacent support.

10. The combination according to claim 8 wherein the jet structures on adjacent ones of said supports are so oriented s to direct cooling fluid at different angles to the surface of the object, the angle of direction increasing from the entry support to the exit support. 

1. Quenching apparatus comprising a support circumferentially and spacedly disposed relative to an object to be quenched, a relatively closely spaced array of jet structures slidably mounted on said support, means for moving each of said jet structures to a selected position on said support relative to the object, and means for supplying a cooling fluid to each of said jet structures, each of said jet structures including antifrictional means for contacting the object, said anti-frictional means being disposed on saiD jet structures so as to space said jet structures predetermined distances from the respectively adjacent surfaces of the object.
 2. Quenching apparatus comprising a support circumferentially and spacedly disposed relative to an object to be quenched, a relatively closely spaced array of jet structures slidably mounted on said support, means for moving each of said jet structures to a selected position on said support relative to the object, and means for supplying a cooling fluid to each of said jet structures, each of said jet structures including a first slide component slidably mounted on a second slide component, means for slidably and adjustably mounting said second slide component on said support, and biasing means on one of said components for urging the said first slide component of said jet structure into contact with the object.
 3. The combination according to claim 1 wherein biasing means are coupled to each of said jet structures for urging said jet structures individually towards the object.
 4. The combination according to claim 1 wherein said moving means are selectively operative to so adjust the relative positions of said jet structures on said support as to accommodate objects having different cross sectional configurations.
 5. The combination according to claim 1 wherein each of said jet structures includes a jet opening and a fluid directing spoon member disposed adjacent said jet opening, said spoon members being shaped so as to form a cooperatively continuous fluid curtain circumferentially surrounding the object.
 6. The combination according to claim 5 wherein at least a portion of each of said spoon members is disposed at a relatively small angle to the adjacent surface of the object to prevent back flow of cooling fluid therealong in a direction opposite to the direction of movement of the object.
 7. The combination according to claim 1 wherein said supplying means include a ring header mounted adjacent said support and circumferentially surrounding the object, and a plurality of flexible conduits coupled individually to said header and to a corresponding one of said jet structures.
 8. The combination according to claim 1 wherein a plurality of said supports are disposed in axially spaced relation, each of said supports having thereon a similar array of said jet structures, said arrays providing a quenching tunnel through which the object to be quenched moves for successive quenching sprays thereby.
 9. The combination according to claim 8 wherein the jet structures on one of said supports are circumferentially displaced relative to the jet structures on an adjacent support.
 10. The combination according to claim 8 wherein the jet structures on adjacent ones of said supports are so oriented s to direct cooling fluid at different angles to the surface of the object, the angle of direction increasing from the entry support to the exit support. 